setuid help

[BALDWIN]

> About setuid in UNIX Sys V: any process that execs a setuid program file
> can switch at will between the processes' real uid and the setuid of
> the file. Thus, it can bounce between these two uid's as often as
> necessary. This is an essentially undocumented feature os UNIX Sys V
> (and derivatives, I hope).

Undocumented?  Please folks, read the manual:

SETUID(2)

	If the effective user ID of the calling process is not super-user,
	but the saved set-user (group) ID from exec(2) is equal to uid
	(gid), the effective user (group) ID is set to uid (gid).
-- 
						Michael Baldwin
						{at&t}!whuxl!mike